1. Field of the Invention
The present invention relates to expandable sand screens and other expandable tubulars. More particularly, the present invention relates to a joint used with expandable sand screens and other expandable tubulars that permits elongation or contraction of the expandable tubulars during a tubular expansion operation within a wellbore.
2. Description of Related Art
Hydrocarbon and other wells are completed by forming a borehole in the earth and then lining the borehole with steel pipe or casing to form a wellbore. After drilling a section of the wellbore, a string of casing is lowered into the wellbore and temporarily hung therein from the surface of the well. Using apparatus known in the art, the casing is cemented into the wellbore by circulating cement into the annular area defined between the outer wall of the casing and the borehole. The combination of cement and casing strengthens the wellbore and facilitates the isolation of certain areas of the formation behind the casing for the production of hydrocarbons. It is common to employ more than one string of casing in the wellbore and the subsequent strings (called “liners”) usually extend back only far enough to overlap with the string thereabove.
Some wells are completed by perforating the casing (or liner) at selected depths where hydrocarbons are found. Hydrocarbons migrate from the formation, through the perforations, and into the cased wellbore. Alternatively, a lower portion of a wellbore may be left open by not lining it with casing, which is known as an open hole completion. To control particle flow from unconsolidated formations of the open hole completion, slotted tubulars or well screens are often employed downhole along the uncased portion of the wellbore. The sand screen is connected to the lower end of a production tubing that hydrocarbons travel through to the surface of the well.
Typically, an expandable sand screen is constructed from three composite layers that include a perforated base pipe, an intermediate filter media, and a perforated outer shroud. The filter media allows hydrocarbons to invade the wellbore, but filters sand and other unwanted particles from entering. A more particular description of an expandable sand screen is described in U.S. Pat. No. 5,901,789, which is incorporated herein by reference in its entirety. Expanding the sand screen into contact with the surrounding formation avoids the need for a gravel pack and increases the size of the wellbore at the level of producing sands. Typically, the expandable sand screen is expanded to a point where its outer wall places a stress on the wall of the wellbore, thereby providing support to the walls of the wellbore to prevent dislocation of particles. This preserves the integrity of the formation during production.
Expansion of an expandable sand screen, a slotted expandable tubular, or a solid expandable tubular may be accomplished by urging a cone-shaped object along the tubular's inner bore or by operating an expander tool having radially outward extending rollers that are fluid powered. A basic arrangement of a conical expander tool is disclosed in U.S. Pat. No. 5,348,095, which is incorporated herein by reference in its entirety. Pulling the expanded conical tool has the effect of expanding a portion of a tubular into sealed engagement with a surrounding formation wall, thereby sealing off the annular region therebetween. More recently, rotary expander tools have been developed. Rotary expander tools employ one or more rows of compliant rollers that are urged outwardly from a body of the expander tool in order to engage and to expand the surrounding tubular. The expander tool is rotated downhole so that the actuated rollers can act against the inner surface of the tubular to be expanded in order to expand the tubular body circumferentially. Radial expander tools are described in U.S. Pat. No. 6,457,532, which is incorporated herein by reference in its entirety. Therefore, expansion means like these provide outwardly radial forces that can expand and plastically deform either the expandable sand screen, the slotted expandable tubular, or the solid expandable tubular for any desired drilling, completion, or production operation. Since an expandable sand screen, a slotted expandable tubular, and a solid expandable tubular possess similar methods of radial expansion and differ mainly in their placement and function in the wellbore, the general term tubular or tubing encompasses all of these applications whether present in a tubular string or as a single tubular section.
Typically, a solid expandable tubular elongates as the metal or material forming the wall of the tubular is expanded radially outward during the expansion operation. The overall amount of elongation of the tubular string depends on factors such as the size of the annular gap and the length of the tubular string. This change in length of the tubular can cause compression of the tubular and present problems in certain instances. For example, buckling of the tubular can occur if the tubular's length increases while radially expanding the tubular from the top down when an end of the tubular string can not extend further to relieve compression due to its contact with a formation. The similar problem occurs when radially expanding from the bottom up while a top of the tubular string is anchored to casing or liner or necessarily held in place with a run-in tool.
On the other hand, an expandable sand screen with slotted tubulars typically shortens during the radial expansion in order to supply the necessary metal or material that comprises the increased diameter of the expanded tubular. This change in length of the tubular can cause tension within the tubular in certain instances. For example, a tubular may break during expansion if it is axially retained at both ends due to contact with a formation. Similarly, the tubular may be prevented from contracting in a bottom up radial expansion, due to the screen being anchored at an upper end to casing or liner.
These examples represent possible problems due to elongation and contraction of tubulars in a wellbore during expansion. However, other operations are envisioned that also fail to accommodate a length change in an expandable tubular as a result of the radial expansion thereof.
Therefore, there exists a need for apparatus and methods that compensate for tension and compression in a tubular string caused by elongation and contraction of tubulars being radially expanded in a wellbore. There exists a further need for a tool or joint that selectively permits axial movement of expandable tubulars in a wellbore in one or both directions when a load is applied thereto.